Use
Refactor | Copy to create a class which is a copy of the selected class. This can be useful, for example, when you need to create a class which has much in common with some existing class and it's not feasible to put the shared functionality in a common superclass.

That's the "Tip of the Day" Intelli-J IDEA has just chosen to show me. You don't get this type of nonsense from Emacs.